Horizontal transmission of Campylobacter jejuni amongst broiler chicks: experimental studies.

Horizontal transmission of Campylobacter jejuni was investigated in campylobacter-free broiler chicks. One hundred and twenty chicks housed individually, were provided with water containing 10(2)-10(9) c.f.u./ml C. jejuni. Colonization was rapid [47 of 73 (64%) positive cloacal cultures within 3 days and 65 of 73 (89%) within 7 days], dependent on C. jejuni strain and inoculum size but independent of chick age. Groups of 5-24 chicks in isolators were exposed to C. jejuni-contaminated water or colonized seeder chicks. Transmission occurred in 2-7 days concurrent with a gradual increase of C. jejuni in litter, water and feed. Environmental samples were culture-negative within 3 days following removal of colonized chicks. Treatment of 1-day-old chicks with adult caecal microbiota did not affect colonization. Treated and control chicks were all C. jejuni-positive within 3 days of seeder challenge.